【Java】同步与异步Timer

public class Timer {

    public void alarm(long millis, Callable callable)
    {
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(millis);
                } catch (Exception e) {
                    e.printStackTrace();
                }
                callable.call();
            }
        }).start();
    }
    public void wait(long millis, Callable callable)
    {
        try {
            Thread.sleep(millis);
        } catch (Exception e) {
            e.printStackTrace();
        }
        callable.call();
    }
}

package hundsun.email.Entity;

public interface Callable {
    /**
     * 回调函数
     */
    public void call();
}

public class TestClass implements Callable {
    static int a = 0;
    @Override
    public void call() {
        a++;
        System.out.println("Timer alarmed!" + a);
    }

    public static void main(String[] args) {
        Timer timer = new Timer();
        timer.alarm(3000, new TestClass());
        System.out.println("-----------");
        timer.wait(3000, new TestClass());
    }
}